Hi all,
I have an electric mountain bike but zero experience or know how when it comes to bikes. I don’t use it often but for months during the few times I have I’ve been having issues when with the chain clunking and coming off. I took it to a local back yard fixer guy and he straightened everything up with the gears and said I should be fine but it hasn’t got any better.
I decided to try and DIY so got on YouTube, inspected the chain and I see at least one broken link. The attached photos are of the broken link, a link that looks different (is this just the missing link?) and also the cassette in case anything looks off. It looks like a lot of the teeth are misshapen to me but someone said this is normal.?!
My plan was to buy a new chain (KMC X10 as engraved on the existing one) and change it over. If the gears were indeed realigned I’m hoping this is the only issue. Does that sound like a plan?
Will the chain come with a missing link? Can I use the one currently on the damaged chain? Is there anything else I chain be weary of? New cassette?
Thanks in advance
by pauliemontana
11 Comments
The chain definitely needs to be replaced. Depending on how many miles are in the drivetrain the cassette and chainrings may need to be replaced as well, since they all wear together.
Replace chain, possibly cassette and regularly inspect.
Both chain and cassette need replacement. The final pic shows broken teeth on the cassette. Make sure to get something high quality/rated for e-bike use.
Also, make sure you’re not shifting while putting down tons of power, that’ll wreck a drivetrain.
Take it to a shop for a chain replacement/repair and to diagnose why a chain failed on a newer bike.
Thanks very much all, it probably hasn’t done 100 miles in total! I’ll start by just replacing the chain. I’ve never done it before or worked on a bike but am handy with DIY in general. Is it just a new chain, a missing link and a chain cutter tool that I need?
My first response was before I saw the later ones 🙂 I’ll take to a shop I guess rather than try DIY
This is the cassette by the way. It looks like shark finned teeth are normal
https://www.worldwidecyclery.com/products/shimano-deore-cs-m4100-10-cassette-10-speed-11-42t-silver
Reduce pedal power when shifting. That may solve your ruining chains and having clunky shifts issue.
Start with a new chain.
It will likely be longer than your existing chain so links may need to be removed to make them the same length. There is a $10 tool for this task.
If it still skips with the new chain, then you will also need a new cassette and cassette removal tool(s). And probably also a new front ring (drivetrain).
I will also add that ebikes often have more chain drops than normal bikes. It might be worth looking into a chain stay device on Amazon.
If indeed you have less than 100 miles on the bike, something is seriously wrong. Either something was assembled wrong from the factory (unlikely but not impossible), or it is your riding style (highly likely). It looks like at minimum you need a new chain, but likely a new cassette as well, as it looks like the third and fourth smallest cogs may have broken teeth (hard to tell in the photo).
Since you have little experience wrenching on bikes, I would probably take it to a shop.
New chain and send it.